1. Field of the Invention
This invention relates to a fire-retardant resin composition obtained by incorporating an aromatic halogen compound and, optionally, a fire-retardant assistant in a resin composition comprising an aromatic copolyester, a polyamide and a polyalkylene phenylene ester or a polyalkylene phenylene ester ether.
2. Description of the Prior Art
U.S. Pat. No. 4,052,481 discloses a resin composition comprising (A) 1 to 98.9% by weight of an aromatic copolyester, (B) 1 to 98.9 % by weight of a polyamide and (C) 0.1 to 98 % by weight of a polyalkylene phenylene ester or a polyalkylene phenylene ester ether, which has superior moldability, mechanical properties, chemical properties, electrical properties and thermal stability, and which is expected to have a very wide range of applications as electric component parts, automobile parts and machine parts. However, the fire retardancy of this resin composition is not sufficient and it has been strongly desired to increase its fire retardancy.
Techniques for rendering such a resin composition fire-retardant are not disclosed in the art.
Methods heretofore suggested for rendering aromatic polyesters fire-retardant include, for example, a method which comprises incorporating a halogenated organic compound, titanium phosphate and antimony oxide in aromatic polyesters (e.g., as disclosed in Japanese patent application (OPI) No. 17556/77 ), and a method involving adding a halogenated phenol to the polymerization system (e.g., as disclosed in Japanese Pat. No. 7470/77 ).
Prior techniques for rendering polyamides fire-retardant include, for example, a method which involves using both a halogenated aliphatic hydrocarbon and a phosphoric acid ester with the polyamide (e.g., as disclosed in Japanese patent application (OPI) No. 19798/77 ), a method involving adding melamine to the polyamide (e.g., as disclosed in Japanese Pat. No. 1994/67 ), a method comprising adding isocyanuric acid to the polyamide (e.g., as disclosed in Japanese Pat. No. 105744/75 ), and a method which comprises adding an amide-type compound to the polyamide and treating the composition with water to prevent the fire retardant from bleeding out of the composition (e.g., as disclosed in Japanese patent application (OPI) No. 16581/77 ).
When the above-described fire retarding compounds are added to the resin composition composed of components (A), (B) and (C) as set forth above, the thermal stability of the composition at the time of melting is poor, and the composition decomposes during processing, for example, on extrusion or injection molding, and the superior properties of the resin composition are markedly deteriorated. Alternatively the fire retardants bleed out with time, or the fire retardancy imparted is not sufficient. Hence, it has been necessary to discover suitable fire retardants for such a resin composition.
It is also known that an aromatic halogen compound or a mixture of an aromatic halogen compound with antimony oxide can be added to a composition comprising an aromatic polyester, a polycarbonate and/or a polyalkylene terephthalate to render the composition fire retardant (e.g., as disclosed in Japanese patent application (OPI) No. 69558/76 ). However, this composition differs from, e.g., that disclosed in U.S. Pat. No. 4,052,481 in terms of the resin components present.